## Search found 19 matches

Tue Apr 08, 2008 5:46 am UTC
Forum: Mathematics
Topic: two-one function
Replies: 41
Views: 5015

### Re: two-one function

obviously this kind of function is not a candidate for hash function

i enjoyed this problem, only for searching such function. sadly, too many explanation that i could not understand . however, i like the generated idea.
Fri Apr 04, 2008 9:52 am UTC
Forum: Mathematics
Topic: two-one function
Replies: 41
Views: 5015

### Re: two-one function

What function were you always told to be careful of at school Sqrt Why did you have to be careful of it? Or, what common functions have a similar graph to that? what about the value at its critical point? @demon lets focus to domain f element [0,1], f:[0,1] -> REAL. actually i do not understand you...
Fri Apr 04, 2008 9:00 am UTC
Forum: Mathematics
Topic: two-one function
Replies: 41
Views: 5015

### two-one function

the one-one function is well defined, but how about two-one function? let we call function f:X->Y is two-one function if every y, element Y, there is exactly two different element X, say x 1 , x 2 such that y=f(x 1 )=f(x 2 ). the problem is to find such function. i get this problem in an intro to re...
Tue Apr 01, 2008 7:05 am UTC
Forum: Mathematics
Topic: Trisecting an angle
Replies: 63
Views: 11468

### Re: Trisecting an angle

hope it help
Mon Mar 31, 2008 12:32 pm UTC
Forum: Mathematics
Topic: Trisecting an angle
Replies: 63
Views: 11468

### Re: Trisecting an angle

i found this from mathematics magazine vol.81 no.1 feb 2008 the title is "a brief history of impossibility" i quote this from there.. suppose we wish to trisect <BOE, which we may assume the central angle of arc BE in a circle (with center O). ...Draw BC parallel to OE and then draw CA wit...
Wed Jan 09, 2008 8:51 am UTC
Forum: Forum Games
Topic: Vending machine!
Replies: 11430
Views: 1005387

### Re: Vending machine!

you take the challenge to unknot it

i plug in my flashdisk
Thu Dec 13, 2007 6:30 am UTC
Forum: Logic Puzzles
Topic: An unusual resolution of the liar's paradox.
Replies: 27
Views: 17297

### Re: An unusual resolution of the liar's paradox.

thank you EricH for the correction: it's suggest me to be more careful with english sentences. i want to make such a good introduction to the Incompleteness Theorem of Godel that break Hilbert faith that mathematics is complete and consistent, so that motivate other mathematician to make unusual sys...
Wed Dec 12, 2007 12:22 pm UTC
Forum: Logic Puzzles
Topic: An unusual resolution of the liar's paradox.
Replies: 27
Views: 17297

### Re: An unusual resolution of the liar's paradox.

i need some inspiration to make an essay about the consequence of liar paradox (and some other logical paradox if any) to breakthrough of fuzzy logic (or dynamic logic). i must make this essay to complete my english course. btw, this is my first exploration to fuzzy world of logic. so what's wrong w...
Wed Dec 05, 2007 8:58 am UTC
Forum: Religious Wars
Topic: CGI vs PHP
Replies: 35
Views: 16453

### Re: CGI vs PHP

i choose php because scripting has a good run-see what happen-edit cycle: the script is easy to redesain. however ajax method is a good option to make web application so similar with desktop application.
Wed Dec 05, 2007 8:08 am UTC
Forum: Mathematics
Topic: Favourite Field of Math?
Replies: 60
Views: 5344

### Re: Favourite Field of Math?

number theory
simply because it's so hard to realize that 8*7 = 56

(Oh me yarm it took more than 3 sec!)
Wed Dec 05, 2007 8:00 am UTC
Forum: Mathematics
Topic: Project Euler 20
Replies: 22
Views: 7699

### Re: Project Euler 20

Since x=SOD(x) (mod 9), the answer (divided by 10^54 to remove zeroes) must be a multiple of 9. (Proof here ) By the same logic, SOD(100!) is divisible by 99. Hope this helps! i believe that 100! divisible by 10^24 but not 10^54, because the the greatest exponent, x, such that 5^x divide 100! is fl...
Tue Dec 04, 2007 8:26 am UTC
Forum: Mathematics
Topic: Inductions!!!
Replies: 10
Views: 1769

### Re: Inductions!!!

reverse induction
flawed induction argument
Tue Dec 04, 2007 8:20 am UTC
Forum: Mathematics
Replies: 367
Views: 84029

### Re: Division by Zero ([s]3[/s] 4 merged threads)

Q: What happens when you don't divide one by anything?
A: You divide one by nothing and get a divide by zero error.
Mon Dec 03, 2007 5:20 am UTC
Forum: Logic Puzzles
Topic: I got one.
Replies: 48
Views: 21876

### Re: I got one.

a classic and more simpler one three person in a row, call them A, B, C in this order. each of them wearing a hat and the hat available are 3 blue and 2 red. each person only can see some person in front of him. C shout, "i do not know what color of my hat", B shout, "me either,"...
Mon Dec 03, 2007 4:57 am UTC
Forum: Logic Puzzles
Topic: Hooray for Hats!
Replies: 9
Views: 4546

### Re: Hooray for Hats!

maybe this kind of problem is relate with the logic behind the statement: He Knows I Know He Knows, i found this problem (proposal of IMO 1991) from Mathematical Miniatures by Svetoslav Savchev and Titu Andreescu.

i found many puzzle-like problem based on this simple statement.
Mon Dec 03, 2007 4:18 am UTC
Topic: Apophysis: Fractal Art
Replies: 82
Views: 13940

### Re: Apophysis: Fractal Art

cool n thanks for the sotware.

but, can anyone tell me about the math behind those fractal.maybe there is some simple formula of chaotic event that create a nice fractal. something like game of chaos
Mon Dec 03, 2007 3:27 am UTC
Forum: Forum Games
Topic: Reach 100 pages before the "Max. post:views ratio" topic!
Replies: 274
Views: 12298

### Re: Reach 100 pages before the "Max. post:views ratio" topic!

Reach 100 pages

Mon Dec 03, 2007 3:26 am UTC
Forum: Forum Games
Topic: Reach 100 pages before the "Max. post:views ratio" topic!
Replies: 274
Views: 12298

### Re: Reach 100 pages before the "Max. post:views ratio" topic!

uh.. division by zer0
Mon Dec 03, 2007 3:25 am UTC
Forum: Forum Games
Topic: Reach 100 pages before the "Max. post:views ratio" topic!
Replies: 274
Views: 12298

ups.. i got it